If there are wires sticking out the back of the AC compressor, the compressor has a rpm counter. The Klima relay compares the compressor to engine rpm to decide if the compressor is working properly. If the compressor is dragging or seized, the Klima relay cuts power to the compressor clutch to save the serpentine belt so as not to strand you. I don't know if nonUS cars have this feature.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD